#include <stdio.h>
int my_strlen(char* str);

int main()
{
    char arr[] = "hello 123";
    printf("%d", my_strlen(arr));
    return 0;
}

int my_strlen(char* str)
{
    if(*str == '\0')
        return 0;
    else
        return  (1+ my_strlen(++str));

}